1. Field of the Invention
This invention relates to optical laminates used as windows, commonly containing at least one rigid layer and one flexible layer.
2. Background Information
Optical laminates are commonly used as protective windows, as in automobiles or airplanes, to protect the occupants from broken glass if something strikes the window with sufficient force to break it. As vehicle speeds increased, work was done to improve the bonding of the rigid layers of the laminate to the elastomeric layers. U.S. Pat. No. 3,341,399, issued Sep. 12, 1967 teaches use of an aqueous solution of a triethoxysilane containing a lower aliphatic alcohol as a treatment on glass surfaces to improve the bonding of polyvinylbutyral between the glass surfaces.
An improved interlayer for laminated safety windows exposed to temperature extremes is taught in Canadian patents 735,398 and 735,399, issued, May 31, 1966. The interlayer is composed of a combination of at least a sheet of transparent organosilicon elastomer and a sheet of synthetic resinous material, such as polyvinylbutyral.
An improved method of bonding a cured sheet of polyurethane to a rigid transparent sheet is taught in U.S. Pat. No. 3,657,057, issued Apr. 18, 1972. A polymerizable polyurethane resin is placed between the cured polyurethane sheet and the rigid transparent sheet before lamination.
A transparent laminated window comprising a pair of glass sheets and an interlayer of polyurethane susceptible of having its adhesion to glass impaired by exposure to moisture is improved by use of an adhesion promoting organosilane coupling agent on a portion of the window between the glass and the polyurethane as taught in U.S. Pat. No. 3,881,043, issued Apr. 29, 1975.
U.S. Pat. No. 3,900,686, issued Aug. 19, 1975, teaches an improved polyurethane composition containing an organic silane and an organic phosphorus acid. The composition can be varied to control the degree of adhesion to glass maintainable under a wide range of humidity and temperature conditions.
A windshield having an antenna incorporated is taught in U.S. pat. No. 3,987,449, issued Oct. 19, 1976. The description of the construction teaches use of a polyurethane containing gamma-glycidoxy-propyltrimethoxysilane in the polyurethane used as the adhesive layer.
A laminated glass-plastic glazing unit comprising an outer and inner sheet of transparent rigid material, at least one being glass, having an interlayer of plasticized polyvinylbutyral is described in U.S. Pat. No. 4,073,986, issued Feb. 14, 1978. The glass and polyvinylbutyral have a continuous layer of transparent polyurethane disposed between them to prevent cold chipping of the glass. An adhesion promoter may be necessary between the glass ply and the polyurethane ply.
A process for producing a non-symmetrical laminate of glass and plastic comprising treating a glass blank with a difunctional silane, forming a first laminate by placing a sheet of an aliphatic polyether polyurethane against the primed glass blank and heating, then placing a polycarbonate or polyacrylate sheet against the polyurethane and heating and pressurizing is taught in U.S. Pat. No. 4,364,786, issued Dec. 21, 1982.
A variety of organosilicone compounds are used as primers in order to cohesively bond polydiorganosiloxane elastomers and resins to organic and inorganic substrates. Plueddemann teaches silanes and bis-silylhydrocarbons that contain a plurality of silicon-bonded alkoxy groups and at least one substituent that is bonded to silicon through oxygen and contain at least four carbon atoms, two of which form a terminal group of the formula CH.sub.2 .dbd.CH-- in U.S. Pat. Nos. 4,659,851, issued Apr. 21, 1987, and 4,719,262, issued Jan. 12, 1988. An improved primer composition for use with amorphous polymers such as polymethylmethacrylate and polycarbonates is disclosed by Baile et al. in U.S. Pat. No. 4,795,775, issued Jan. 3, 1989.